KR101998433B1 - Composition containing 1,4-butanediol - Google Patents

Abstract

It is an object of the present invention to provide a 1,4-butanediol-containing composition having high thermal stability as compared with conventional 1,4BG. The present invention relates to a 1,4-butanediol-containing composition wherein the concentration of 1,4-butanediol is 99.00 wt% or more and 99.99 wt% or less, and the concentration of the amide compound in terms of nitrogen atom is 1.0 to 50 wt ppm.

Description

COMPOUND CONTAINING 1,4-BUTANEDIOL [0001]

The present invention relates to 1,4-butanediol containing compositions.

1,4-butanediol (hereinafter abbreviated as " 1,4BG ") is known to be a very useful substance used as a raw material for various solvents and derivatives. Conventionally, various methods for industrially producing 1,4BG have been developed. For example, diacetoxy, which is an intermediate obtained by subjecting butadiene to raw material butadiene, acetic acid and oxygen using an acetoxylation reaction, Butene is hydrogenated and hydrolyzed to produce 1,4BG (Patent Document 1), and a process for producing 1,4BG by hydrogenating them using maleic acid, succinic acid, maleic anhydride and / or fumaric acid as raw materials to obtain 1,4- , 4BG (Patent Document 2), a process for producing 1,4BG by hydrogenating butene diol obtained by contacting acetylene as a raw material with a formaldehyde aqueous solution (Patent Document 3) and the like .

Though tetrahydrofuran (hereinafter, sometimes abbreviated as "THF") which is a derivative containing 1,4BG as a raw material is generally used as a solvent, a polyether polyol (specifically, polytetramethylene ether glycol) It is also used as a raw material. As a method for producing THF from 1,4BG, Patent Document 4 discloses a method for continuously producing THF by reacting a reaction mixture containing 1,4BG on a heteropolyacid catalyst, wherein 2- (4- Hydroxybutoxy) -tetrahydrofuran and a basic nitrogen component of less than 1 ppm, the lifetime of the heteropoly acid catalyst can be prolonged. Further, there is a polybutylene terephthalate (hereinafter abbreviated as "PBT" in some cases) as another derivative containing 1,4BG as a raw material. In Patent Literature 5, 1,4BG, which is a raw material, (The concentration of the catalyst raw material, the reaction pressure, the ratio of terephthalic acid and 1,4BG, and the like) so that 1,4BG becomes THF so as not to become unnecessary.

Japanese Patent Application Laid-Open No. 52-7909 Japanese Patent Publication No. 2930141 Japanese Patent Publication No. 62-4174 Japanese Patent Publication No. 2006-503050 Japanese Laid-Open Patent Publication No. 2005-350659

The 1,4BG obtained by the methods described in the above Patent Documents 1 to 3 is a 1,4BG untreated low purifying raw material containing impurities generated from unreacted raw materials, by-products, catalysts used in the production process, Therefore, in order to use it as a raw material for the derivatives described in Patent Document 4 or Patent Document 5, generally, 1,4BG having good quality is used by purifying such as distillation so as to become a specification suitable for the purpose of use of 1,4BG .

However, when the purified high-quality 1,4BG is actually applied to the application, the quality is worse than that obtained immediately after the purification, and in particular, the heat of 1,4BG when 1,4BG is used as the raw material of PBT It was found that the stability deteriorated (THF was generated in 1,4BG).

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a 1,4-butanediol-containing composition having higher thermal stability than 1,4BG.

DISCLOSURE OF THE INVENTION The present inventors have intensively studied in order to solve the above problems. As a result of intensive studies, the present inventors found that 1,4BG obtained by purification contains a trace amount of an acid component that can not be removed by conventional purification, It is surprisingly found that among the nitrogen-containing compounds conventionally considered to be the cause of the deterioration of the catalyst, 1,4BG is converted into THF, and an induction product accompanied by a rise in pH when 1,4BG is brought into contact with a base component such as an alkali metal It is possible to suppress the deterioration of the catalyst and suppress the conversion of 1,4BG into THF by mixing the amide having a small influence of the catalyst deterioration during the production at a specific concentration range and as a result, The present invention has been accomplished on the basis of these findings.

The present invention has been achieved on the basis of this finding, and it is based on the following [1] to [4].

[1] A 1,4-butanediol-containing composition wherein the concentration of 1,4-butanediol is 99.00 wt% or more and 99.99 wt% or less, and the concentration of the amide compound in terms of nitrogen atom is 1.0 to 50 wt ppm.

[2] The 1,4-butanediol-containing composition according to [1], wherein the pH is 5.0 or more and 7.9 or less.

[3] A process for producing a polyester by the polycondensation reaction of 1,4-butanediol with at least one of a dicarboxylic acid and a dicarboxylic acid ester, wherein a concentration of 1,4-butanediol is 99.00% By weight or more and 99.99% by weight or less, and the concentration of the amide compound in terms of nitrogen atom is 1.0 to 50 parts by weight per 100 parts by weight of the 1,4-butanediol-containing composition.

[4] Use of a 1,4-butanediol-containing composition having a concentration of 1,4-butanediol of 99.00% by weight or more and 99.99% by weight or less as the raw material and a concentration of the amide compound in terms of nitrogen atom equivalent of 1.0 to 50% In the presence of an acid catalyst having a pKa value of 4 or less in the reactor, dehydrating cyclization of 1,4-butanediol to obtain tetrahydrofuran.

The 1,4-butanediol-containing composition of the present invention has high thermal stability and can be used as a raw material for a derivative, and it is possible to suppress the poisoning of the catalyst during coloring and post-processing.

Hereinafter, the present invention will be described in more detail.

The 1,4BG contained in the 1,4-butanediol-containing composition of the present invention can be obtained by a conventionally known production method. For example, an acetoxylation reaction is carried out using raw materials butadiene, acetic acid and oxygen to obtain an intermediate diacetoxybutene, 1,4-butanediol, 1,4-butanediol, 1,4-butanediol, 1,4BG obtained by hydrogenating maleic anhydride and / or fumaric acid as a raw material, crude 1,4BG obtained by hydrogenating butene diol obtained by contacting acetylene with formaldehyde aqueous solution as a raw material, oxidation of propylene 1,4BG obtained by hydrogenation of succinic acid obtained by fermentation method, 1,4BG obtained by direct fermentation from biomass such as sugar, and the like.

The concentration of 1,4BG in the 1,4-butanediol-containing composition of the present invention is 99.00 wt% or more and 99.99 wt% or less, preferably 99.20 wt% or more and 99.97 wt% or less, more preferably 99.50 wt% or more and 99.95 wt% % Or less. The higher the concentration of 1,4BG, the higher the purification cost, and the lower the value, the more likely the byproducts are produced in the production of the polyester and the more easily the product is colored.

The 1,4-butanediol-containing composition of the present invention needs to contain an amide compound. Although the 1,4-butanediol-containing composition of the present invention is thermally stable with amide compounds, the reason for this is not necessarily clear, but 1,4-butanediol has a trace amount of a THF formation promoting substance below the detection limit And it is presumed that the amide compound can enhance the thermal stability by rendering the promoting material harmless. Of the amide compounds, those containing a carboxylic acid amide are preferred. As the carboxylic acid amide, a primary amide, a secondary amide or a tertiary amide can be used, and the number of N-substituted substituents is in the range of 0 to 2, and N-alkyl substituted amide, N-alkenyl substituted amide, N- Aryl substituted amides and the like are used. The substituent may contain a hetero atom, and a plurality of substituents may be the same or different. Examples of the substituent on the carbonyl side include a hydrogen atom, an alkyl group, an alkenyl group, and an aryl group. The substituents may be linked to each other to form a ring. From the standpoint of suppressing side reactions and decomposition when the 1,4-butanediol-containing composition of the present invention is treated in the distillation column, the substituent on the carbonyl side is preferably an alkyl group.

The carboxylic acid amide always coexists with 1,4-butanediol and continuously exhibits the thermal stability effect. In addition, when the 1,4-butanediol-containing composition is treated in a distillation tower, A compound having a boiling point at 160 캜 to 300 캜 under atmospheric pressure is preferably used, more preferably 165 to 280 캜, and particularly preferably 170 to 250 캜. When the boiling point is higher than that, it is difficult to adjust the nitrogen concentration in the 1,4-butanediol-containing composition of the present invention. When the boiling point is too low, it is difficult to adjust the nitrogen concentration, .

As a specific example of the amide compound of the present invention, it is preferable to use acetamide as the primary amide, N-methylacetamide and N-ethylacetamide as the secondary amide, and N, N-dimethylacetamide as the tertiary amide 2-pyrrolidone as the secondary amide, N-methylpyrrolidone as the tertiary amide, N-ethylpyrrolidone, N-vinylpyrrolidone, 2-pyrrolidone as the tertiary amide, aromatic amides such as amide, And cyclic amides such as piperidone and N-methylpiperidone. More preferred examples thereof include acetamide, N-methylacetamide, 2-pyrrolidone and N-methylpyrrolidone. Particularly preferred are acetamide, 2-pyrrolidone and N-methylpyrrolidone. The amide contained in the 1,4-butanediol-containing composition of the present invention may be one kind or two or more kinds.

The 1,4-butanediol-containing composition of the present invention is characterized by containing 1.0 to 50 ppm by weight of the above-described amide compound in terms of nitrogen atom. The 1,4-butanediol-containing composition having this concentration range can be prepared by adding 1,4-butanediol to commercially available 1,4-butanediol, 1,4-butanediol, 1,4-butanediol, 1,4- . It is also possible to prepare them by adding them in the course of the process of the raw material or the 1,4BG production process by the above-described conventionally known 1,4BG production method.

For example, in the case of obtaining diacetoxybutene, which is an intermediate obtained by carrying out an acetoxylation reaction using raw materials butadiene, acetic acid and oxygen, and by hydrolyzing the diacetoxybutene and water, Amide may be introduced to produce diacetoxybutene. In the subsequent hydrogenation step, 1,4-diacetoxybutane containing nitrogen may be prepared by introducing an amide. Also, in the hydrolysis step, an amide may be introduced to obtain a mixture containing 1,4-butanediol and water and 1-acetoxy-4-hydroxybutane. Alternatively, an amide may be introduced into a distillation column for obtaining a purified high-purity product 1,4BG separated from the mixture or a hydrogenation process for removing impurities. When a hydrogenation reaction mixture containing 1,4BG, gamma-butyrolactone and tetrahydrofuran obtained by hydrogenating maleic acid, succinic acid, maleic anhydride and / or fumaric acid as raw materials is obtained, May be introduced into the reaction mixture. When added during the process of the production process as described above, the added amount may be added in an amount larger than 50 ppm by weight. That is, the addition amount may be adjusted so that the final concentration of the amide in the 1,4-butanediol-containing composition is 1.0 to 50 ppm by weight as nitrogen atom conversion.

In the present invention, when the amide compound is added to the 1,4-butanediol production process, there is no particular limitation on the boiling point and the concentration, and thus it may be added in any state of gas, liquid or solid. It is also possible to dissolve the amide compound in a raw material, a product, a solvent, water, or the like. The content of the amide compound contained in advance for other purposes may be adjusted in advance.

It is also possible to directly add an amide compound to 1,4-butanediol having a purity of not less than 99% obtained by purifying 1,4BG produced by the above-described conventional method, and to add it to not less than 1.0 ppm by weight and not more than 50 ppm by weight. In this case, it is naturally necessary to add a small amount of the amide-added product 1,4-butanediol so that the purity thereof is 99 wt% or more and 99.99 wt% or less as defined in the present invention.

The concentration of the amide compound contained in the 1,4-butanediol-containing composition of the present invention is preferably 1.0 ppm by weight or more and 50 ppm by weight or less, more preferably 3.0 ppm by weight or less and 40 ppm by weight or less, Is not less than 10 ppm by weight and not more than 25 ppm by weight. In contrast, when the nitrogen atom-converted concentration is higher than that, the catalyst poisoning is increased when the catalyst is colored or when it is guided to other products such as polyester. When the concentration in terms of nitrogen atom is too low, the effect of improving the quality such as thermal stability is deteriorated.

The 1,4-butanediol-containing composition of the present invention is preferably pH 5.0 to pH 7.9, more preferably 5.5 to 7.0, and particularly preferably 5.7 to 6.9. When the pH is higher than this, there is a tendency that the catalyst poisoning is increased when the catalyst is colored or when it is guided to other products such as polyester. When the pH is too low, the effect of improving the thermal stability due to the inclusion of the amide compound tends to be lowered.

The 1,4-butanediol-containing composition of the present invention is preferably used for producing polyesters such as PBT and polybutylene succinate, gamma butyrolactone or tetrahydrofuran.

For example, in the case of producing a polyester by using the 1,4-butanediol-containing composition of the present invention as a raw material, at least one of 1,4-butanediol, dicarboxylic acid and dicarboxylic acid ester is subjected to a polycondensation reaction Wherein the concentration of 1,4-butanediol is 99.00% by weight or more and 99.99% by weight or less and the concentration of the amide compound in terms of nitrogen atom is 1.0 to 50 ppm by weight, .

Further, among the polyesters, it is more preferable to use the 1,4-butanediol-containing composition of the present invention when producing PBT, and a known production method can be used for the production thereof. For example, a known production method of PBT is largely divided into a so-called direct polymerization method using terephthalic acid as the main raw material and an ester exchange method using a dialkyl terephthalate ester as the main raw material. In either case, 1,4-butanediol is polymerized There is a demand for a process for producing PBT which is easy to be converted to tetrahydrofuran during the reaction and has a low conversion rate of tetrahydrofuran. In the direct polymerization method, water is produced by the initial esterification reaction, and in the ester exchange method, alcohol is produced by the initial transesterification reaction. However, the stability of the raw material, easiness of treatment of the effluent, , And direct polymerization is preferable from the viewpoint of the improvement effect of the present invention. As the production method of PBT having a low conversion rate of tetrahydrofuran and a low raw material loss, the 1,4-butanediol-containing composition having high heat stability of the present invention is very effective.

In the production of PBT, the amide of the present invention is preferably a compound having a boiling point at 160 ° C to 300 ° C under an atmospheric pressure, in order to allow the chewing-point component to flow out during the production process.

For example, as a method for producing THF using the 1,4-butanediol-containing composition of the present invention, a known production method of dehydrating and cyclizing 1,4BG with THF by an acid catalyst can be applied. The reactor for carrying out the dehydrating cyclization reaction of the present invention may be a fixed bed reactor packed with a solid catalyst such as a cation exchange resin, a solid bed reactor using a solid catalyst, or a homogeneous acid catalyst dissolvable in a raw material A tubular reactor or a tubular reactor may be used. It is also possible to obtain THF by discharging a solution containing THF in the liquid phase in the reactor and by-product water from the reactor and purifying it in a post-process such as a distillation column, but it is also possible to partially or totally remove the THF from the gas phase of the reactor, It is also possible to extract it as a gas containing water.

The acid catalyst may be any acid catalyst having a pKa value of 4 or less, but preferably an organic acid or phosphoric acid which is a sulfonic acid, a cation exchange resin, a heteropoly acid, a phosphoric acid and the like, more preferably a metal- Sulfonic acid. Specific examples thereof include aromatic sulfonic acid derivatives such as para toluenesulfonic acid, benzenesulfonic acid, orthotoluenesulfonic acid and methotoluenesulfonic acid, and chain type aliphatic sulfonic acid derivatives such as butanesulfonic acid, hexanesulfonic acid, octanesulfonic acid and nonanesulfonic acid. The carbon skeleton may have functional groups other than sulfonic acid. These acid catalysts may be used singly or in combination of two or more. As the acid catalyst, paratoluenesulfonic acid is particularly preferably used.

These acid catalysts are usually neutralized and deteriorated in the presence of a basic component. A method of adding an inorganic base to increase the thermal stability of 1,4-butanediol, and the like, but when this method is used, the acid catalyst is deteriorated. On the other hand, the 1,4-butanediol-containing composition having high heat stability of the present invention does not promote deterioration of the acid catalyst because the basicity thereof is not high.

In addition, when tetrahydrofuran is produced using the 1,4-butanediol-containing composition of the present invention, the amount of 2- (4-hydroxybutoxy) -tetrahydrofuran in the reactor is reduced in the presence of water as by- , It is possible to effectively suppress the generation of by-product solid matter.

Generally, derivatives of 1,4BG such as THF, PBT and the like are prepared using an acid catalyst. Therefore, it is desired to use a 1,4BG composition having a pH of 7 or less and a high thermal stability.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the scope of the present invention is exceeded.

In the following Examples, 1,4-butanediol and tetrahydrofuran were analyzed by gas chromatography, and 1,4-butanediol was determined by the corrected area percentage method using the Karl Fischer method (manufactured by Mitsubishi Chemical Corporation "Quot; CA-21 "). Tetrahydrofuran was calculated by internal standard method (internal standard: n-octadecane). The concentration of the nitrogen-containing compound in terms of nitrogen atom conversion was calculated from the amount of the added amine.

PBT Synthesis Examples (Examples 10 to 12 and Comparative Example 4) Various analyzes were conducted by the following methods. The tetrahydrofuran was analyzed by calculating the organic component by the modified area percent method using gas chromatography, and calibrating it with the water content by the Karl Fischer method (measured by "CA-200" manufactured by Mitsubishi Chemical Corporation). The amount of tetrahydrofuran produced was expressed in terms of mole% relative to terephthalic acid, and the conversion was determined. The intrinsic viscosity (IV) of PBT was determined by the following procedure using a Ubbelohde type viscometer. That is, using a mixed solvent of phenol / tetrachloroethane (1/1 by mass), the polymer solution having a concentration of 1.0 g / dl at 30 캜 and the falling water solely of the solvent were measured and found from the following equation.

IV = ((1 + 4K _H ? _Sp ) ^0.5 -1) / (2K _H C)

_{However, η sp = (η / η} 0) -1 a, η is the polymer solution fall seconds, η ₀ is the number of seconds of the solvent to fall, C is the polymer solution concentration (g / ㎗), K _H is the Huggins constant. K _H was 0.33.

The pellet color tone of the PBT was obtained by charging the pellet polyester into a cell for powder measurement of a cylindrical shape having an inner diameter of 30 mm and a depth of 12 mm by using a colorimetric colorimeter Z300A (manufactured by Nippon Denshoku Kogyo Co., Ltd.) The b value by the color coordinates of the Hunter color difference equation in the Lab display system described in Reference Example 1 of Z 8730 was obtained as a simple average value of the values measured at four points by rotating the measuring cell by 90 degrees by the reflection method.

≪ Example 1 >

To 1,4-butanediol (containing 1,4-butanediol: 99.6% by weight) having a nitrogen atom concentration of 5.0 ppm by weight was added to 25.0 g of commercially available 1,4-butanediol (manufactured by Mitsubishi Chemical Corporation) Was prepared. The pH was measured and found to be 5.6.

This composition was transferred to a 100 ml stainless steel autoclave, and the container was purged with nitrogen, and then heated at 242 占 폚 for 1 hour. After the autoclave was cooled, 1,4-butanediol-containing composition was taken out and analyzed for the amount of tetrahydrofuran to be produced, and it was 800 ppm by weight. The results are shown in Table 1.

≪ Example 2 >

Example 1 was carried out in the same manner as in Example 1 except that 1.2 ppm by weight of 2-pyrrolidone was used in place of acetamide in terms of nitrogen atom concentration. The pH of the 1,4-butanediol-containing composition before heating was 5.5. The amount of tetrahydrofuran in the 1,4-butanediol-containing composition after heating was analyzed and found to be 2998 ppm by weight. The results are shown in Table 1.

≪ Example 3 >

Example 1 was carried out in the same manner as in Example 1 except that 5.0 ppm by weight of 2-pyrrolidone was used in place of acetamide in terms of nitrogen atom concentration. The pH of the 1,4-butanediol-containing composition before heating was 5.5. The amount of tetrahydrofuran in the 1,4-butanediol-containing composition after heating was analyzed and found to be 2180 ppm by weight. The results are shown in Table 1.

<Example 4>

Example 1 was carried out in the same manner as in Example 1 except that 21.0 wt ppm of 2-pyrrolidone was used instead of acetamide in terms of nitrogen atom concentration. The pH of the 1,4-butanediol-containing composition before heating was 5.5. The amount of tetrahydrofuran produced in the 1,4-butanediol-containing composition after heating was analyzed and found to be 978 ppm by weight. The results are shown in Table 1.

&Lt; Comparative Example 7 &

Example 1 was carried out in the same manner as in Example 1 except that 50.0 wt ppm of 2-pyrrolidone was used in place of acetamide in terms of nitrogen atom concentration. The pH of the 1,4-butanediol-containing composition before heating was 5.5. The amount of tetrahydrofuran produced in the 1,4-butanediol-containing composition after heating was analyzed and found to be 2109 ppm by weight. The results are shown in Table 1.

&Lt; Example 6 &gt;

Example 1 was carried out in the same manner as in Example 1 except that 1.2 ppm by weight of N-methylpyrrolidone was used in place of acetamide in terms of nitrogen atom concentration. The pH of the 1,4-butanediol-containing composition before heating was 5.5. The amount of tetrahydrofuran produced in the 1,4-butanediol-containing composition after heating was analyzed and found to be 4020 ppm by weight. The results are shown in Table 1.

&Lt; Example 7 &gt;

Example 1 was carried out in the same manner as in Example 1 except that N-methylpyrrolidone was used in an amount of 5.0 ppm by weight in terms of nitrogen atom concentration instead of acetamide. The pH of the 1,4-butanediol-containing composition before heating was 5.5. The amount of tetrahydrofuran generated in the 1,4-butanediol-containing composition after heating was analyzed and found to be 1300 ppm by weight. The results are shown in Table 1.

&Lt; Example 8 &gt;

Example 1 was carried out in the same manner as in Example 1, except that 21.0 wt ppm of N-methylpyrrolidone was used in place of acetamide in terms of nitrogen atom concentration. The pH of the 1,4-butanediol-containing composition before heating was 5.5. The amount of tetrahydrofuran produced in the 1,4-butanediol-containing composition after heating was analyzed and found to be 704 ppm by weight. The results are shown in Table 1.

&Lt; Comparative Example 8 &gt;

Example 1 was carried out in the same manner as in Example 1 except that 50.0 wt ppm of N-methylpyrrolidone was used in place of acetamide in terms of nitrogen atom concentration. The pH of the 1,4-butanediol-containing composition before heating was 5.5. The amount of tetrahydrofuran produced in the 1,4-butanediol-containing composition after heating was analyzed and found to be 1335 ppm by weight. The results are shown in Table 1.

&Lt; Comparative Example 1 &

Example 1 was carried out in the same manner as in Example 1 except that commercially available 1,4-butanediol was heated without adding acetamide. The amide in 1,4-butanediol before heating was below the detection limit in terms of nitrogen atom concentration. The pH was 5.5. The amount of tetrahydrofuran generated in 1,4-butanediol after heating was analyzed and found to be 6800 ppm by weight. The results are shown in Table 1.

&Lt; Comparative Example 2 &

Example 1 was the same as Example 1 except that in Example 1, N-methylpyrrolidone was used in an amount of 0.5 ppm by weight in terms of nitrogen atom concentration instead of acetamide. The pH of the 1,4-butanediol-containing composition before heating was 5.5. The amount of tetrahydrofuran in the 1,4-butanediol-containing composition after heating was analyzed and found to be 12507 ppm by weight. The results are shown in Table 1.

&Lt; Comparative Example 3 &

Example 1 was the same as Example 1 except that 0.1 ppm by weight of 2-pyrrolidone was used in place of acetamide in terms of nitrogen atom concentration. The pH of the 1,4-butanediol-containing composition before heating was 5.5. The amount of tetrahydrofuran produced in the 1,4-butanediol-containing composition after heating was analyzed and found to be 7773 ppm by weight. The results are shown in Table 1.

&Lt; Example 10 &gt;

Manufacture of PBT

Containing composition containing 113 g of terephthalic acid and 4.0 ppm by weight of 2-pyrrolidone in terms of nitrogen atom in a reaction vessel equipped with a stirrer, a nitrogen inlet, a heating device, a thermometer and an exhaust port for pressure- 0.7 g of a solution prepared by dissolving 184 g (concentration of 1,4 BG: 99.4 wt%, pH 5.5) and 6 wt% of tetrabutyl titanate as a catalyst in advance was introduced, and the inside of the system was subjected to nitrogen- Respectively. The inside of the system was heated to 150 ° C with stirring, then the temperature was elevated at 220 ° C under normal pressure for 1 hour, and the esterification reaction was carried out while allowing water to be generated for 2 hours to flow out. Next, the magnesium acetate 4 hydrate was dissolved in water, and a 1,4-butanediol solution (magnesium acetate 4 hydrate, water, 1,4-butanediol mass ratio of 1 wt.% Of magnesium acetate 4 hydrate dissolved in 1,4BG 1: 2: 97). Next, the temperature was raised to 245 ° C over 1 hour, the pressure was reduced to 0.07 ° C over 1.5 hours, the polycondensation reaction was carried out at the same reduced pressure for 1.1 hours, and the reaction system was returned to atmospheric pressure and the polycondensation was terminated. The obtained PBT was taken out from the bottom of the reaction vessel as a strand, put into water at 10 캜 and removed, and the strand was cut with a cutter to obtain pellet-shaped PBT. The color-b indicating the degree of coloration of the obtained PBT was 2.2.

The time from the start of decompression to the end of polycondensation after the addition of magnesium acetate was regarded as the polycondensation time, and the intrinsic viscosity / polycondensation time was taken as the polycondensation rate. The polycondensation rate was 0.37 dl / g / h. The THF conversion rate was expressed as molarity per mol of injected terephthalic acid by analyzing the amount of THF in the effluent during the esterification reaction. The THF conversion rate was 63.7 mol%. The results are shown in Table 2.

&Lt; Example 11 &gt;

PBT was obtained in the same manner as in Example 10 except that the 1,4-butanediol-containing composition containing 6.6 wt ppm of 2-pyrrolidone in terms of nitrogen atom was used in Example 10. As a result, the polycondensation rate was 0.37 dl / g / h. The color-b showing the degree of coloration of the obtained PBT was 2.9. The results are shown in Table 2.

&Lt; Example 12 &gt;

PBT was obtained in the same manner as in Example 10, except that the 1,4-butanediol-containing composition containing 20.2 wt ppm of 2-pyrrolidone in terms of nitrogen atom was used in Example 10. As a result, the polycondensation rate was 0.37 dl / g / h. The THF conversion rate was 64.6%. The color-b indicating the degree of coloration of the obtained PBT was 3.3. The results are shown in Table 2.

&Lt; Comparative Example 4 &

Example 10 was carried out in the same manner as in Example 10 except that 1,4-butanediol was replaced with commercially available 1,4BG containing no 2-pyrrolidone (below the detection limit) in place of the 1,4-butanediol- PBT was obtained. As a result, the polycondensation rate was 0.36 dl / g / h. The THF conversion rate was 78.6%. The results are shown in Table 2.

&Lt; Reference Example 1 &

Preparation of THF

2.0 g of commercially available 1,4-butanediol (manufactured by Mitsubishi Chemical Corporation) and 1.2 mg of paratoluenesulfonic acid monohydrate were added to 9 ml of the glass vial, and the mixture was stirred at 60 캜 for 2 hours.

The tetrahydrofuran content after heating was analyzed and found to be 1003 ppm by weight. The results are shown in Table 3.

<Reference Example 2>

2-pyrrolidone was added to commercially available 1,4-butanediol (manufactured by Mitsubishi Chemical Corporation) to prepare a 1,4-butanediol-containing composition containing 2-pyrrolidone in a concentration of 40.0 wt ppm in terms of nitrogen atom . 2.0 g of the 1,4-butanediol-containing composition was placed in a 9 ml glass vial, 1.2 ㎎ of paratoluenesulfonic acid monohydrate was added, and the mixture was stirred at 60 캜 for 2 hours.

The tetrahydrofuran content after heating was analyzed and found to be 1,100 ppm by weight. The results are shown in Table 3.

<Reference Example 3>

A composition containing 1,4-butanediol containing 60.0 wt ppm of 2-pyrrolidone in terms of nitrogen atom was used in the same manner as in Reference Example 2.

The tetrahydrofuran content after heating was analyzed and found to be 1146 ppm by weight. The results are shown in Table 3.

<Reference Example 4>

Except that 1,4-butanediol-containing composition containing 80.0 wt ppm of 2-pyrrolidone in terms of nitrogen atom was used.

The tetrahydrofuran content after heating was analyzed and found to be 1290 ppm by weight. The results are shown in Table 3.

<Reference Example 5>

20.0 g of commercially available 1,4-butanediol (manufactured by Mitsubishi Chemical Corporation) was transferred to a 100 ml stainless steel autoclave equipped with an internal tube made of Teflon (registered trademark), 12 mg of para-toluenesulfonic acid monohydrate was added, After completion of the reaction, the mixture was stirred at 140 ° C for 2 hours.

The amount of generated tetrahydrofuran was analyzed and found to be 6.7% by weight. The results are shown in Table 3.

<Reference Example 6>

Butanediol containing 40.0 wt ppm of 2-pyrrolidone in terms of nitrogen atom was used in place of commercially available 1,4-butanediol.

The tetrahydrofuran content after heating was analyzed and found to be 6.6% by weight. The results are shown in Table 3.

<Reference Example 7>

Butanediol-containing composition containing 40.0 wt ppm of ammonia in terms of nitrogen atom in place of 2-pyrrolidone was used in place of 2-pyrrolidone.

The tetrahydrofuran content after heating was analyzed and found to be 709 ppm by weight. The results are shown in Table 3.

<Reference Example 8>

Except that 1,4-butanediol-containing composition containing ammonia in a concentration of 60.0 wt ppm in terms of nitrogen atom was used instead of 2-pyrrolidone in Reference Example 2.

The tetrahydrofuran content after heating was analyzed and found to be 614 ppm by weight. The results are shown in Table 3.

<Reference Example 9>

Butanediol-containing composition containing 80.0 wt. Ppm of ammonia in terms of nitrogen atom in place of 2-pyrrolidone was used in place of 2-pyrrolidone.

The tetrahydrofuran content after heating was analyzed and found to be 90 ppm by weight. The results are shown in Table 3.

<Reference Example 10>

Except that 1,4-butanediol-containing compositions containing ammonia in a concentration of 40.0 wt ppm in terms of nitrogen atom were used in place of commercially available 1,4-butanediol.

The tetrahydrofuran content after heating was analyzed and found to be 1.0% by weight. The results are shown in Table 3.

&Lt; Example 13 &gt;

300.0 g of 1,4BG containing 10.0 wt ppm of 2-pyrrolidone in terms of nitrogen atom concentration was added to a glass 500-mL flask reactor equipped with a glass cooling tube for the outflow, and 1.50 g of para-toluenesulfonic acid 0.5% by weight based on the total weight of the composition) was injected, and the internal temperature was heated to 145 캜 using an oil bath. After the internal liquid temperature stabilized at 145 占 폚, 265.8 g of the effluent containing THF condensed in the cooling tube was taken out of the glass storage tank and 34.2 g of the residual liquid (2.8 mg in the residual liquid) was obtained in the flask reactor. The results are shown in Table 4.

&Lt; Comparative Example 5 &

The same procedure as in Example 13 was carried out except that 1,4BG containing 0.1 ppm by weight or less of 2-pyrrolidone in terms of nitrogen atom in the raw material 1,4BG was used.

260.9 g of the effluent containing THF was taken out to the glass storage tank to obtain 34.7 g (the amount of by-product solid in the residual liquid: 42.0 mg) in the flask reactor. The results are shown in Table 4.

&Lt; Comparative Example 6 &gt;

The same procedure as in Example 13 was carried out except that 1,4BG containing ammonia in a concentration of 10.0 ppm by weight in terms of nitrogen atom was used as the raw material 1,4BG.

268.4 g of the effluent containing THF was taken out of the glass storage tank to obtain 31.6 g of the residual liquid (67.1 mg of byproduct in the residual liquid) in the flask reactor. The results are shown in Table 4.

From Examples 1 to 4, Comparative Example 7, Examples 6 to 8, and Comparative Example 8 and Comparative Examples 1 to 3, the 1,4-butanediol-containing composition containing the specific amount of the nitrogen- It can be seen that the 1,4BG-containing composition can suppress the amount of THF generation and is highly thermally stable when used as a raw material in the production of PBT.

It is also understood that Examples 10 to 12 in which PBT is produced using the 1,4-butanediol-containing composition of the present invention can suppress the THF conversion rate as compared with Comparative Example 4.

In Reference Examples 2 to 4, in which tetrahydrofuran is produced using the 1,4-butanediol-containing composition of the present invention, the amount of THF formation is the same as in Reference Example 1 and no catalyst deterioration is found. On the other hand, in Reference Examples 7 to 9 in which ammonia having a high basicity was added, it was found that the amount of THF decreased with the increase of the amount of nitrogen compound, and the catalyst deteriorated. The same is true even if the reaction temperature is raised higher than that in Reference Examples 5, 6 and 10. From Example 13 and Comparative Examples 5 and 6, it can be seen that the production of solid matter can be inhibited by the production of tetrahydrofuran using the 1,4-butanediol-containing composition of the present invention.

While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. This application is related to Japanese Patent Application (Japanese Patent Application No. 2011-151716) filed on July 8, 2011, and Japanese Patent Application (Japanese Patent Application No. 2011-241572) filed on November 2, 2011 , The contents of which are incorporated herein by reference.

Claims (4)

The concentration of 1,4-butanediol is 99.00% by weight or more and 99.99% by weight or less, the concentration of the carboxylic acid amide in terms of nitrogen atom is 1.0 to 25 ppm by weight,
Wherein the carboxylic acid amide is at least one of an acetamide and an N-alkyl substituted amide satisfying the conditions of the following carboxylic acid amide.
The condition of the carboxylic acid amide: the number of the N-substituted substituents is in the range of 1 to 2, the plural substituents may be the same or different, and the substituent on the carbonyl side is an alkyl group, . The method according to claim 1,
A composition containing 1,4-butanediol having a pH of from 5.0 to 7.9. A process for producing a polyester by the polycondensation reaction of 1,4-butanediol with at least one of a dicarboxylic acid and a dicarboxylic acid ester, wherein the concentration of 1,4-butanediol is 99.00% by weight or more and 99.99% by weight %, And the concentration of the carboxylic acid amide in terms of nitrogen atom is 1.0 to 25 ppm by weight,
Wherein the carboxylic acid amide is at least one of an acetamide and an N-alkyl substituted amide satisfying the conditions of the following carboxylic acid amide.
The condition of the carboxylic acid amide: the number of the N-substituted substituents is in the range of 1 to 2, the plural substituents may be the same or different, and the substituent on the carbonyl side is an alkyl group, . Wherein the concentration of 1,4-butanediol is 99.00% by weight or more and 99.99% by weight or less and the concentration of the carboxylic acid amide in terms of nitrogen atom is 1.0 to 25 ppm by weight and the carboxylic acid amide is acetamide and / Alkyl substituted amide satisfying the conditions of the following carboxylic acid amide, in the presence of an acid catalyst having a pKa value of 4 or less in a reactor, 1,4-butanediol To obtain tetrahydrofuran. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt;
The condition of the carboxylic acid amide: the number of the N-substituted substituents is in the range of 1 to 2, the plural substituents may be the same or different, and the substituent on the carbonyl side is an alkyl group, .